Mechanics and materials (Paper 1)

Question 1

What is a moment?

Answer 1

The force multiplied by the perpendicular distance from the line of action of the force to the point

Question 2

What is the principle of moments?

Answer 2

For a system in equilibrium, the sum of anticlockwise movements around a pivot is equal to the sum of clockwise movements.

Question 3

What is a couple?

Answer 3

A pair of coplanar forces where the two forces are equal in magnitude but opposite in direction.

Question 4

How does terminal speed occur?

Answer 4

Frictional forces and driving force on an object is equal, therefore there’s no resultant force and no acceleration so it travels at a constant speed.

Question 5

What does Hooke’s Law state?

Answer 5

The extension of an object is directly proportional to the force applied up to the limit of proportionality.

Question 6

What are the definitions of plastic and brittle?

Answer 6

Plastic-A material will experience a large amount of extension as the load is increased, especially beyond the elastic limit.
Brittle-Does not extend very far before plastically deforming. Will fracture at low extensions.

Question 7

What is an elastic and inelastic collision?

Answer 7

Elastic: Both momentum and kinetic energy are conserved in a collision.
Inelastic: Only momentum is conserved in a collision.